Merge pull request #102 from guillermobox/develop

Added mean for statistical functions
Fixed function mean to support complex values, added more tests to min and max.
Implemented support for multiplying vectors with matrices
Removed support for comparing complex numbers
Statistics functions `max` and `min` now return the max and min of the flattened array in case of multidimensional arrays.
Renamed options to `math.options.format.precision` and `math.options.matrix.defaultType`
Updated docs on options